1. Field of the Invention
The present invention relates to a printer and a printing method, and in particular to a printer and a printing method thereof capable of printing a copy-forgery-inhibiting pattern image having a function of constraining duplication or use of a duplicated matter, together with an image to be constrained from the duplication.
2. Description of the Related Art
Heretofore, for the purpose of inhibiting or constraining duplication of a ledger sheet, a resident card or the like, contents thereof have been printed on a sheet applied with special printing, that is, the so-called forgery preventing sheet. The forgery preventing sheet is a sheet for a master copy of which is hard to see for mankind, however a sheet that can emboss characters such as “COPY INHIBIT” in case of duplicating with the use of a copying machine. This produces such an effect that causes a person to hesitate to use a duplicated matter thereof. Further, the form or the like printed on the forgery preventing sheet exhibits such an effect that duplication may be prevented or controlled. However, the above-mentioned forgery preventing sheet causes a problem of expensive costs in comparison with sheets usually used. Further, only characters which are set during the manufacture of the forgery preventing sheet becomes visible, and accordingly, the forgery preventing sheet is limited in use, that is, it is not flexible in its use.
On the contrary, in Japanese Patent Laid-Open Publication No. 2001-197297, it is disclosed that image data called to be a copy-forgery-inhibited pattern is generated in addition to printing data, and these data are printed being superposed with each other by a printer. The printed image including the copy-forgery-inhibited pattern merely exhibits a pattern or a background image on its original as printed matter is viewed by the human eyes, but predetermined characters or a certain image become visible if it is duplicated. Thus, this original gives a diversionary effect similar to that of the forgery preventing sheet.
The copy-forgery-inhibited pattern image can be composed of two zones, that is, a zone in which an image similar to that of the original remains in a duplicated matter, and a zone in which an image present in the original vanishes on a duplicated matter or a zone in which an image has a tone which is thinner than that of the zone in which the image remains. The copy-forgery-inhibited pattern image, which can be composed of these two zones, can have a substantially equal density between both zones in a condition in which it is printed out. That is, it is required to constitute the printed-out copy-forgery-inhibited pattern image in such a way that characters or the like which become visible on a duplicated matter is hidden, and accordingly, it can hardly be recognized by the human eyes in a macroscopic view. The image zone that is hidden in a printed-out matter of a copy-forgery-inhibited pattern image but becomes visible so as to be recognized through the human visual sense on a duplicated matter on which the printed-out matter is duplicated is so called as “latent image”. Further, the image zone which vanishes away on a duplicated matter or which has a density lower than that of the latent image that is visible on the duplicated matter is so conveniently called as “background (or background image)”. Further, the copy-forgery-inhibited pattern image can be basically composed of the latent image and the background image. It is noted that the latent image is also called as a foreground image in view of the terminology of a user interface.
It is noted that the copy-forgery-inhibited pattern printing should not be limited to the configuration as stated above, but there may be such a configuration that a string or the like is reproducible at a recognizable level on a duplicated matter. That is, even in such a condition that a string is designated as a background part, and characters are exhibited in a reversed condition during duplication, the copy-forgery-inhibited pattern printing may achieve its purpose.
By the way, in a system in which image data is delivered from a host unit to a printing apparatus for printing, if a copy-forgery-inhibited pattern image as stated above is printed together with image data, a certain instruction relating to copy-forgery-inhibited pattern printing is delivered from the host unit to the printing apparatus in order to print the copy-forgery-inhibited pattern image. As one configuration thereof, there has been presented such a configuration that information exhibiting a copy-forgery-inhibited pattern image is transmitted as instructing information to the printing apparatus together with image data, and accordingly, the printing apparatus generates a copy-forgery-inhibited pattern image, based on the information (Japanese Patent Laid-Open Publication No. 2001-346032). Further, as another configuration, there has been known such a configuration that a copy-forgery-inhibited pattern image previously held in the printing apparatus is synthesized to image data received from a host unit in response to information instructing addition of a copy-forgery-inhibited pattern and delivered from the host unit (Japanese Patent Laid-Open Publication No. 2003-072166). Further, there has been also known such a configuration that a copy-forgery-inhibited pattern image is generated for original data read by a printing apparatus and usual printing data sent from the host unit even though no instruction is delivered from a host unit, and is then synthesized to the printing data (Japanese Patent Laid-Open Publication No. H07-231384).
However, should various patterns be present as to the above-mentioned copy-forgery-inhibited pattern printing, a problem of the contention between the host unit and the printing apparatus would be caused as to the copy-forgery-inhibited pattern printing in a printing system in which the host unit and the printing apparatus are connected to each other by way of an internet or the like.
That is, there would be caused such a case that the printing apparatus holds or generates a copy-forgery-inhibited pattern by itself while the host unit transmits information of a copy-forgery-inhibited pattern image to the printing apparatus. In this case, setting information as to a copy-forgery-inhibited pattern such as a content of a copy-forgery-inhibited pattern instructed by the host unit would be different from setting information as to a copy-forgery-inhibited pattern owned by the printing apparatus. Further, this difference in the setting information would cause hindrance to the build-up of an effective printing system.
Further, in the case of a multifunctional printing apparatus such as an MFP, it would be considered that the supervisor therefor sets printing of a copy-forgery-inhibited pattern image, that is, setting information for a copy-forgery-inhibited pattern solely owned by the printing apparatus is applied to an image from a specific user or an IP address in the host unit, or a specific image. In this case, it is desirable that the setting information of a copy-forgery-inhibited pattern owned by the printing apparatus is applied as far as possible, irrespective of the setting information of a copy-forgery-inhibited pattern transmitted from the host unit.